Wire terminal



H. F. MASON Nov. 2, 1954 WIRE TERMINAL Filed Oct. 6, 1950 //v VENTO R. Ho wa/w F Mnsorv BY HIS ATTORNEYS. Hn mas, K/EcH, F 057-51? & Hmems 51 United States Patent WIRE TERMINAL Howard F. Mason, Los Angeles, Calif., assignor to Mason Electric Corporation, Los Angeles, Calif., a corporation of California Application October 6, 1950, Serial No. 188,733 Claims. (Cl. 339-248) This invention relates to a connector or a securing device and more particularly to a wire terminal for releasable attachment or clamping of an electrical conductor where weight, size, efliciency,. cost, and simplicity of connecting and disconnecting are prime or mandatory requisites. Further, the invention relates to a connector having the aforementioned characteristics which when used to connect two conductors in series occupies approximately the space that would be occupiedby an equal length of conductor and insulation'permitting a joinder to be made that simulates a unitlength of conductor. In this manner, a releasable connection may be provided in any electrical circuit, especially in inaccessible or closely confined quarters that are usually found, for example, in cable conduits of aircraft and the control equipment therefor.

The now conventional devices used to releasably connect a conductor or wire to a terminal usually entail the deformation of the conductor, as by coiling it about aclamping. screw, adapting an eyelet log to the wire for engagement with a stud or screw, providing a bulky plug and receptacle, etc. Further, various means have been devised to render the connection firm and free from the effects of vibration and strain, but these are generally attended by complication of the connection and/or bulkiness whereby versatility is limited. In general, however, these devices were designed to accommodate certain requirements, usually limited in scope, and have varying costs depending upon the complexity thereof. The present invention contemplates resolute simplicity of construction of a wire terminal or. connector embodying combined advantageous characteristics not heretofore included in a single structure. It is an object of this invention, therefore, to provide a wire terminal or connector having integrated therein such multiple advanta es.

lt is another object of this invention to provide a wire terminal to receive and securely clamp a conductor that may be straight-line insertable in the terminal.

It is another object toprovide a connector or terminal for engagement of two conductors whereby the conductors may be straight-line insertable in the connector to provide a series connection for the conductors.

It is another object to provide a series connection of two conductors by a connector or terminal that occupies an efiective space approximating that of a comparable length of conductor and its insulation.

It is another objection to provide a terminal having the aforementioned characteristics that is relatively compact in size to receive and securely clamp a conductor and render the engagement substantially free from the effects of vibration.

It is still another object to provide a wire term nal, the clamping pressure of which may be predetermined to accommodate a sufficient electrical connection but preclude excessive deformation of the wire.

Another object is to provide a connector to straightline receive a stranded conductor and secure the conductor in shake-proof relation to the connector.

Another object is to provide a wire terminal of simplicity comprising a channel element and a screw.

Another object is to provide a wire terminal for the connection of two conductors with a means to prevent the component parts thereof from becoming entirely disassociated.

It is another object to provide a connector or a plu- 2,693,585 Patented Nov. 2, 1954 electrical conduits whereby the conveniently interrupted to isolate various circuits whereby they may be tested for voltage, current, continuity, and otherwise.

The invention also has for its objects to provide such means that are positive in operation, convenient in use, easily installed in working position and easily disconnected therefrom, economical of manufacture, relatively simple, and of general superiority and serviceability.

The invention also comprises novel details of construction and novel combinations and arrangements or" parts, which will more fully appear in the course of the following description. However, the drawing merely shows, and the following description merely describes, several embodiments of the present invention, which are given by way of illustration or example only.

In the drawing, like reference characters designate similar parts in the several views, wherein:

Fig. 1 is a sectional side elevational view of the present invention showing a dual application of the terminal in association with two conductors;

Fig. 2 is a cross-sectional view of the channel member taken along the line 2-2 of Fig. 1;

Fig. 3 is a cross-sectional view of the channel and associated screw taken along the line 33 of Fig. 1;

Fig. 4 is a side elevational view of a modification of the terminal of Fig. 1 showing the channel sides as partially cut away;

Fig. 5 is a top view of the modification shown in Fig. 4;

Figs. 6 and 7 are top rality thereof in certain electrical path may be and side elevational views, respectively, of a modification of the terminal of Fig. 1 showing a means to prevent removal of the screw;

Figs. 8 and 9 are a top view and a side elevational view partially in phantom, respectively, showing another modification of the wire-receiving terminal;

Fig. 10 is a sectional side elevational view of the terminal of Fig. l and including a bar for increased current carrying capacity;

Fig. 11 is a sectional side elevational view of the terminal of Fig. 1 and including a retainer to limit the removal of either of the screws individually;

Fig. 12 is a sectional side elevational view of a modification' of the terminal of Fig. 1 showing a means to additionally secure a conductor;

Fig. 13 is a sectional side elevational view of a modificationof the Wire terminal embodying the characteristics of the terminals shown in Figs. 10, 11, and 12;

Fig. 14 is a sectional side elevational view, reduced in scale, showing. a single connector that may be adapted to terminal boards, bus bars, etc.; and

Figs. 15, 16 and 17 are representative of the stages of structure of the terminal in the method of fabrication thereof.

Referring now to Figs. 1, 2 and 3, there is illustrated a dual or duplex representation of the invention in preferred basic form. As will become apparent hereinafter, only one: half the structure shown is necessary in certain usage. The terminal or connector comprises a conductive unitary channel element 20 and two screws 21 and 22 disposed therein. The channel is substantially U-shaped in cross section having a base 23' and to upturned side portions 24 and 25. The sides as illustrated are substantially parallel. toeach other; however, it is within contemplation that these sides may taper or vary from one channel extremity to the other for reasons that will hereafter become apparent. Adjacent the screw 21 is an insulated electrical conductor 27 with the insulation partially stripped therefrom to provide a protruding solid wire 28 that is straight-line or straight-away and insertably disposed intermediate the screw 21 and the base 23. Adjacent the screw 22 is another insulated electrical conductor 29 with the insulation partially removed therefrom to provide a protruding stranded wire 30 that is insertably disposed intermediate the screw 22 and the base 23. The screws provide for clamping engagement of the conductors 27 and 29' to the channel base 23 to furnish a current carrying path between the conductors.

The difierent types of wires are illustrated to indicate the versatility of the terminal in connecting any type of conductor, electrical or otherwise, without any structural changes of the terminal. The screws 21 and 22 are concave-tipped or recessed and flat-tipped, respectively, the former providing a more effective grip for wires that are subject totension. The type of screw used for illustrative purposes in'the drawings is the now conventional Allen head screw, the advantage of which will hereinafter become apparent. However, this is not to be construed as a limitation, for all types of head-driven screws or otherwise are contemplated for use herein.

Referring to Fig. 3, the screw 22 is shown in relation to the channel being embraced between the side portions 24 and and retained therebetween by a plurality of impressions 32 and 33 formed respectively in the inner faces of the side portions. These impressions are preferably thread-like in nature to match the pitch of the screw and are formed in a manner to be explained hereinafter. As threads, therefore, the impressions in one side portion are a continuation of the impressions in the opposite side portion and provide a noncontinuous helical thread to receive the screw.

In preferred construction it is desirable that the screw be retained within the confines of the channel with an engagement comparable to a wringing tolerance fit. This may be accomplished by provision of an inclination of the side portions toward one another to gradually reduce the opening for the screw, or the sizes of the channel and the screw may be selected so that the effective diameter of the screw is slightly greater than the effective diameter of the threads formed in the side portions. In either manner of construction the side portions exert a lateral and binding pressure upon the screw at the surface of engagement therewith thereby minimizing the possibility of the screw coming loose under conditions of vibration.

The efficiency of the clamping of the wire and the pressure thereupon may be readily understood by recognizing the type and character of the material of which the channel is fabricated. Preferably the channel is made of a resilient conductive material, for example, beryllium copper, whereby the side portions under lateral pressure due to the insertion of the screw will yieldably separate. The channel element is sufliciently hard or has-been hardened so that the impressed threads in the side portions will stand considerable shearing stress. When the screw is driven down to clamp the wire intermediate the base and the screw, the reactive force components applied axially to the screw increases the frictional engagement of the threads in the side portions with the screw threads. As the clamping pressure increases, it is apparent, therefore, that the side portions will tend -to spread laterally away from each other with an increase in the lateral pressure upon the screw, as hereinafter will become apparent. Accordingly, the wire is firmly clamped to the channel element and the screw is secured by the resilient side portions effecting a substantially vibration or shake resistant en-' gagement of the wire to the terminal.

The clamp or grip applied to the wire with this type of structure may be limited to a predetermined amount by appropriate selection of the gauge of metal used for the channel element. In many instances of mass production, wires are pre-cut to exact length and laced together in cable form prior to installation or attachment to other wires, bus bars, or other terminals. It is mandatory, therefore, that each wire be preserved and not mutiliated or changed in length necessitating the cable to be rejected or discarded. A wire, either solid or stranded, when subjected to high pressure will distort and shear, especially in the case of the stranded conductor. By limiting the pressure applied to the wire to an amount commensurable with the shear value, the wire will not be subjected to mutilation or change in length. As hereinbefore indicated, when the screw is bottomed upon the wire clamping it to the channel element, the side portions then tend to spread laterally.

Continued rotation of the screw increases the amount of spread until the threads disengage and then re-engage one pitch removed therefrom. In this manner the clamping pressure applied to the wire is limited to prevent a rupture of the wire and yet provide a firm and complete electrical connection.

As hereinbefore indicated, the channel element 20 need not necessarily have parallel sides 24 and 25, but may taper toward one another providing a channel of d1fi 6l'6!1l'. Widths at either extremity thereof. This is desirable when connecting wires of different gauge nunl bet to on another in order that the conductor may substantially occupy the floor of the channel to provide a sufficient bulk for the screw to engage.

Figs. 4 and 5 show a modification of the terminal shown in Fig. 1, wherein the wire connected to either extremity may be secured or removed with a minimum effect upon the other wire engagement. As hereinbefore indicated, when a screw is introduced and continually rotated after it is bottomed upon a wire, the resilient side portions move laterally in accommodation. With a continuous side portion the lateral movement at either extremity of the channel will be transmitted to a certain degree to alter the lateral pressure exerted upon the screw at the other extremity. To alleviate this interaction and maintain the engagement substantially independent, the side portions may be cut away intermediate the ends thereof as indicated by the arrow 35 providing side members 36, 37, and 38, 39 for each side portion 24 and 25, respectively. The shape of the cut may be varied depending upon the desired use considering the necessary resiliency of the side members. In Figs. 4 and 5, the cut is substantially rectangular and is carried down to the base 23 of the channel element 20. Providing independent side members may be accomplished by making the cut very small. The resiilency of the opposed side members 36 and 38 or 37 and 39 may be varied by lateral positioning or varying the width of the cut. Theutility of such variation may be recognized in that it may be desirable electrically to connect, wires of different gauge numbers, composition or other characteristics requiring a different amount of pressure applied thereto. Further, the cutsmay be V-shaped or angled with respect to the base 23 and in general satisfy any desired connection requirement. An incidental use of the cut shown in Figs. 4 and 5 is to receive a strap or a clamp for attachment to a terminal board or other object to locate and secure thechannel element and the connected wires.

Figs. 6 and 7 show a modified structure of one of the extremities of the channel shown in Fig. 1, whereby the vertical movement of the screw within the channel is limited toprevent inadvertent removal or loss of the screw when attaching or releasing a wire. This protective feature is illustrated by a pair of formed tips or bent prongs 40 for each of the side portions 24 and 25 which extend therefrom and partially over the head of the screw 22. The prongs are directed in such a manner as to not interfere with direct access to the head of the screw along the axis thereof. The advantage of the Allen head screw now may be more apparent in that.

the driving wrench therefor is capable of entrance into the head of the screw without interference by or with the effectiveness .of the prongs. For increased structural rlgidlty of the prongs, the side portions 24 and 25 may be of such a height as to entirely envelop the screw, the prongs extending transversely thereover from the outer edge of the side portions. It is within contemplation that the prongs may be of any suitable size or shape, or one or more in number, to accomplish the above-described purpose.

Figs. 8 and 9 show part of a channel element 20 as modrfiedto receive and grip an insulated wire to provide additional precaution against breakage and/or releasing of the wire due to vibration. The channel element 20 is deformed at its extremity to provide a flare 42 that is contiguous with the base 23 and the two side portions 24 and 25. The conductor 29 occupies a position with respect to the channel element so that wire 30 is disposed intermediate the screw 22 and the base 23 and the insulation rests within the contour of the flare 42. After the screw has been tightened to secure the wire 30 to the base 23, the flare 42 is crimped or pinched about the conductor '29 firmly engaging the insulation thereof, thereby providing a supplemental clamp or grip through the conductor to effectively resist extreme vibration as well as permitting the conductor to be subjected to considerable tension without pulling free of the terminal.

Fig. 10 shows a wire terminal substantially the same as seen in Fig. 1 augmented by ameans to increase the current carrying capacity of the terminal. The channel element 20 as described hereinabove may be increased or decreased in physical size to accommodate the maximum current predicted, but in consideration of mass production methods and standardization of itemsof manufacture, it is expedient to produce identical parts in quantities.

The capacity of the wire terminal may be increased by the addition of a bar 45 of conductive material disposed within the channel elements 20 and in surface contact with the base thereof. The conductor 29- is straight-line inserted as before, but in this instance intermediate the screw 22 and the bar 45, the screw being driven down to firmly clamp the wire 30. Thus the cross-sectional area of the terminal may be increased to a desired amount to accommodate any increase in the current load without any adverse effect upon the resiliency of the side portions that would otherwise occur if the size or gauge of the channel element were altered.

Fig. 11 shows the dual terminal of Fig. 1, having added thereto a formed strip 47 that serves to prevent complete removal of either screw if loosened individually, as well as to increase the current carrying capacity of the terminal if necessary. Further, as will be explained, the wire is clamped and retained firmly with a minimum of distortion thereof.

The strip 47 is made of an integral length of durable metal that is disposed within the channel 20 and intermediate the screws 21 and 22 and the wires 28 (not shown) and 34). The width of the strip is substantially equal the channel width to provide a support surface to engage with the screws. The strip comprises a longitudinal portion 48 and upturned members 49 and 50 at each end thereof. The members 49 and 50 include main portions 51 and 52, respectively, along the sides of their associated screws and terminating in bent noses 53 and 54, respectively, extending over the heads of the screws. If it is desirable to remove one wire, as is illustrated on the left-hand side of Fig. 11, the screw 21, the releasing screw, will be prevented from being completely removed by the nose 53 for the longitudinal portion 48 is retained firm with respect to the channel 20 through the clamping of the screw 22.

If desired, the strip 47 may be made of a non-conductive material. Irrespective of the material, however, the strip serves the additional purpose of causing the wire 3! to be clamped or pinched without any abrasive action thereupon.

Fig. 12 is another modified form of the terminal shown in Fig. 1 wherein the base 23 of the channel 20 is provided with cavities or recesses 56 in approximate axial alignment with the longitudinal axes of the screws. This embodiment is useful in extreme instances where the terminal and connected wire are subject to tensile stress tending to forcibly separate the connection. The engagement hereinbefore described is substantially frictional and is satisfactory for most electrical joining, but certain requirements may necessitate the additional feature of rendering the connection secure against tension. For example, it may be necessary after connection is made to draw the conductor through a small conduit where dependency is placed upon the strength of the wire. The crimp that is provided by the screw 22 forcibly depressing the wire 30 into the recess 56 increases the tensile bind period. It is noted that the screws 21 and 22 may be provided with conical noses 57 to increase the efficiency of the engagement.

Fig. 13 is another modified form of the terminal shown in Fig. l, and including the features shown in Figs. 10, 11 and 12, in combination. The bar 45 is located within the channel and is provided with recesses 60 that are spaced apart to substantially align with the screws 21 and 22. and the longitudinal portion 48 of the strip 47 is dented or deformed as indicated at 61 to match the recesses 60. The advantages of this structure have been indicated with reference to the individual Figs. 10, 11, and 12 as described hereinbefore.

Fig. 14 is a side elevational view, in section, of a terminal that may be adapted to terminal boards or bus bars and is useful for providing a plurality of leads from a single source of power to energize a plurality of circuits. The sides 24 and 25 are only of sufiicient length to assure auflicient lateral pressure upon the screw. The base 23 is provided with a hole 63 that may be used to receive a stud, screw, or otherwise, to secure the terminal to a bus bar or other conducting element.

rom the foregoing it is now apparent that any combination of the above-described alterations or modifications may be integrated into a single terminal or connector to satisfy any particular design requirement.

Figs. 15, 16 and 17 show the stages of the manufacture of the terminal channel shown in Fig. 1 and the method whereby the impressions or threads may be formed therein. Fig. 15 shows an end view of a strip of deformable material, 65 that is to be formed into a channel element. A screw 66, preferably made of tooled steel, is suitably positioned normal to the strip preferably along the longitudinal center line thereof. The strip is then folded along, its length as best seen in Fig. 16 forming the U-shaped channel 21' having the base 23 and the side portions 24 and 25. Pressure is then applied to the side portions adjacent the screw 66 whereby the threads of the screw are firmly pressed into the inner faces of the side portions as best seen in- Fig. 17 forming the impressions of the screw threads therein. In order that the channel element retain its required shape, it is heat-treated sufliciently to be stress relieved as well as provide resiliency to the side portions and hardening of the formed impressions.

If desired, prior to heat treating, the screw 66 may be removed and the side portions pressed toward each other to reduce the distance between the outer edges thereof. In this manner, an increased lateral pressure may be applied to the commercial screw that is inserted within the confines of the channel.

While the invention and method of manufacture that have been illustrated and described are regarded as preferred, the construction and methods are, of course, subject to modification without departing from the spirit and scope of the invention. It is therefore not desired to restrict the invention to the particular forms of construction or method therefor illustrated and described, but to cover all modifications that may fall within the scope of the appended claims.

I claim as my invention:

1. In a wire terminal for electrical connection of two conductors in series relation, the combination of: a unitary element of conductive material having a base and two upturned side portions providing a substantially U- shaped channel; a plurality of threads at each extremity of said element formed in the inner faces of said side portions, the threads in opposite faces cooperating with each other; screws for the threads of each extremity receivable between said side portions; and a strip having a longitudinal portion substantially the length of and disposed within said channel between said screws and said base, and including an upturned member at each extremity thereof, each of said members including a main portion adjacent said longitudinal portion and a bent nose extending from said main portion at the outer end thereof and partially over a said screw whereby said conductors may be introduced at the extremities of said element between said strip and said base and clamped therebetween by pressure of said screws and wherein the clamping engagement of one of said screws may be released for removal of the associated conductor, the associated nose of said strip being operable to prevent inadvertent removal of said releasing screw.

2. In a wire terminal for electrical connection of two conductors, the combination of: a unitary element of conductive material having a base and two upturned resilient side portions providing a substantially U-shaped channel; a plurality of threads adjacent each end of said element and formed in the inner faces of said side portions, the threads in opposite faces cooperating with each other; screws for said threads receivable between said side portions; a bar of conductive material substantially the length of said element and disposed in said channel; a strip having a longitudinal portion substantially the length of and disposed in said channel superimposed over said bar, said strip including at least one upturned member at one extremity thereof, said member including a main portion adjacent said longitudinal portion and a bent nose extending from said main portion at least partially over one of said screws, whereby said conductors may be introduced at the extremities of said element between said bar and said strip and clamped therebetween by pressure of said screws and wherein the clamping engagement effected by one of said screws may be limitedly released for removal of the conductor associated therewith, said screw being nonremovable from said element due to restraining engagement with said nose.

3. In a device according to claim 2 wherein the longitudinal portion of said strip is deformed intermediate its ends providing at least one downwardly projecting segment, and said bar includes a depressed portion in the surface thereof underlying said segment.

4. In a wire terminal for electrical connection of two conductors in series relation, the combination 'of: a unitary element of conductive material having a base and two upturned side portions providing a substantially U- shaped channel; a plurality of threads at each extremity of said element formed in the inner faces of said side portions, the threads in opposite faces cooperating with each other; screws for the threads of each extremity receivable between said side portions; and a strip having a longitudinal portion disposed within said channel and between said screws and said base, and including at least one upturned member at one extremity thereof, said member including a main portion adjacent said longitudinal portion and a bent nose extending from said main portion partially over one of said screws whereby one of said conductors may be introduced at an extremity of said element between said strip and said base and clamped therebetween by pressure of the adjacent screw and wherein the clamping engagement of said last-mentioned screw may be released for removal of the associated conductor, said nose being operable to prevent inadvertent removal of said releasing screw.

5. In a wire terminal for electrical connection of two conductors in series relation, the combination of: a unitary element of conductive material having a base and two upturned side portions providing a substantially U- shaped channel; a plurality of threads at each extremity of said element formed in the inner faces of said side portions, the threads in opposite faces cooperating with each other; screws for the threads of each extremity receivable between said side portions; and a strip having a longitudinal portion disposed within said channel and between said screws and said base, and including at least one upturned member at one extremity thereof, said member including a main portion adjacent said longitudinal portion and means carried by said main portion extending at least partially over one of said screws whereby one of said conductors may be introduced at an extremity of said element between said strip and said base and clamped therebetween by pressure of the adjacent screw and wherein the clamping engagement of said lastmentioned screw may be released for removal of the associated conductor, said means being operable to prevent inadvertent removal of said releasing screw.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 573,397 De Grafrenried Dec. 15, 1896 1,103,749 Finkelstein July 14, 1914 1,266,441 Finkelstein May 14, 1918 1,717,276 Stubbers June 11, 1929 1,767,903 Sparkes June 24, 1930 1,936,869 Deaver Nov. 28, 1933 2,088,481 Mylius July 27, 1937 2,114,188 Johansson Apr. 12, 1938 FOREIGN PATENTS Number Country Date 585,343 Germany Ian. 5, 1933 717,901 Germany Feb. 25, 1942 

